I'm not sure what the limit is. MySQL limits tend to be dictated by the OS that is being used. The more columns you have the larger the database file will be. You should try to avoid having many empty columns in a database design, even if you are using varchar instead of char. Try to think ahead in your design to what indexes you will create to speed up searching. You obviously don't want to create 300 indexes (don't know if you even can) and you want to avoid full database searches, which is what happens with no indexes.
Going on a relevant tangent here. What could you need 300 columns for? I'd be hard pressed to think of a dataset that would have 300 unique pieces of data. Perhaps you can make your columns into records? A simple example to clarify. I see many database designs that create maybe 10 or more columns to store various phone numbers (home, work, cell, fax, beeper, other, etc.). A better design would be to make them records in a "phone number" database with a description field to indicate what phone number it is. This gives you the ability to store unlimited phones numbers and to easily search for a phone number (i.e. reverse lookup). Plus, you can create one index to index all you phone numbers for quick searching. I would not split your data into separate tables. If you have to, create a table with a column called "field name" where you can specify what type of information a record holds. On Tuesday, October 15, 2002, at 09:40 PM, Andrew Kuebler wrote: > I have a table I need to build with about 300 columns and I'm > concerned about performance issues, however, I would only extract from > the table what I need, not all 300 at one time. -- Brent Baisley Systems Architect Landover Associates, Inc. Search & Advisory Services for Advanced Technology Environments p: 212.759.6400/800.759.0577 --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
